Well bit



M. NEWTON Sept 9,

WELL, BIT

Filed Oct. 8' 1940 Patented Sept. 9, 1941 UNITED STATES PATENT OFFICE WELL BIT Max A. Newton, Avenal. Calif.

Application October 8, 1940, Serial No. 360,271

(Cl. Z55-61) 13 Claims.

This invention relates to a drilling tool and relates more particularly to a bit for use in the rotary method of well drilling. A general object of this invention is to provide a practical, effective, long wearing well bit.

Another object of this invention is to provide an improved rotary well drilling bit embodying a primary set of cutting parts which are initially active in the drilling operation, and a secondary set of cutting parts which become eil'ective or active in the drilling of 'the well when the primary cutting parts are worn to a given extent.

Another object of this invention is to provide a well drilling bit of the drag type in which sets or series of cutting blades are successively and automatically made operative without withdrawing the bit from the well. In the drillingr of deep wells the bit is secured to the lower end of a drilling string made up of a large number of pipe sections and the string is rotated and fed downwardly so that the bit drills away the earth formation. The cutting parts of a typical rotary drag type wear away very rapidly and the bit must be removed from the well for replacement by a new or reconditioned tool after only a short period oi' use. The removal of the worn bit necessitates the withdrawal V'and disconnection of the long string of drill pipe and the insertion of the new bit requires the assembling and lowering of the pipe string into the well. which operations are tedious and time consuming. The improved bit of the present invention embodying sets of cutting parts which are successively made operative, has a much longereffective .life 'thanv a typical bit and, therefore, appreciably reduces i and run-y the time and labor involved in pulling ning in the drilling string. p Y v v Another object of this invention'is to'y provide a well drilling bitV embodying cutting'parts iixed to the bit body and preliminary or primary cutting parts shiftable relative to the body and dependably held in active positionsv where they extend downwardly beyond the .iixed cutting parts to be active in the drilling operation until worn dull, whereupon they are released to move up so that the iixed blades come vinto play to continue the drilling operation. The bit of the present invention is characterized by the preliminary cutting parts which are initially held xed to the body until worn away to a given extent at which time they are automatically freed to retract from the well bottom thus conditioning the rigid blades to carry on the drilling operation.

Another object of the invention is to provide a well drilling bit of the character referred to which maintains the diameter or gauge of the well bore throughout the operation of both sets of cutting blades.

Another object of this invention is to provide a well bit of the character referred to that is simple and sturdy in construction and which is devoid of springs, latches, plungers, and other devices liable to failor become inoperative.

A further object of this invention is to provide a well bit of the character referred to that is inexpensive and that is adapted to be easily and inexpensively reconditioned after use.

The various objects and features of my invention will be fully understood from the following detailed description of typical preferred forms and applications of my invention, throughout which description reference is made to the accompanying drawing, in which:

vare fragmentary vertical detailed sectional views illustrating alternative means for releasably retaining the shiftable 'blades in their active positions.

The present invention is capable of embodiment in well drilling tools varying greatly in design and intended use. In the drawing I have illustrated. the features of the invention employed in a typical embodiment, it being understood that the invention is not to be construed as limited or restricted to the specic :form and application of the invention herein disclosed. While I have shown the invention embodied in a bit for cutting a full diameter bore it is to be understood that the invention may be embodied in core drills, pilot bits, etc. and where I herein employ the bit" it is to be understood as meaning any well drilling tool useful in cutting away the earth formation.

The well bit provided by this invention may be said to comprise, generally a body III, spaced wings or cutting blades I l rigid with the body Ill, shiftable cutting blades l2, and means I3 for holding the shiftable blades l 2 extended to act on the earth formation and releasable when the blades I 2 are worn away to a given extent.

The body I l is adapted to be connected with the lower end of a rotary well drilling string and is provided with suitable means for facilitating its connection with the string. In the typical The major portion of the body Il is an elongate cylindrical element whose lower end is suitably rounded or curved. A central longitudinal opening I extends into the body Il from its upper end to receive the circulating iluid. It will be observed that the body il may be of simple sturdy design.

The wings or cutting parts II serve to carry the shiftable blades I2 and operate to form the outerpartofthewellandtocuttheboreto gauge when the shii'table blades I2 are worn and the means I3 is released. There is preferably a plurality of circumferentially spaced blades II. In the particular case illustrated there are three equally spaced blades II of identical or like design. In accordance with the invention the blades II are xed to or rigid with thebody Il. The blades Il may be integral parts of the body Il as illustrated, or maybe secured to the body by welding, by bolts, or the like. The ilxed blades II are elongate vertically extending parts which project downwardly and outwardly from the body Il. The blades l I may extend tnrdughout the major portion of the body I. and preferably project a substantial distance downwardly from the body. The forward faces I5 of the blades II are dat and may lie in vertical planes which are radial relative to the central vertical axis of the bit. The blades II are preferably quite thick and their outer rear comers are bevelled off as at l1. The outer edges Il of the blades II may be substantially vertical and serve to guide the bit and to maintain the full gauge of the bit. The lower ends of the blades II are bevelled oflr at their rear sides leaving cutting edges Il. The cutting edges Il may be straight and horizontal and are preferably of equal extent. The xed cutting blades II are preferably hard-faced throughout their wear taking parts, said parts being provided with inserts of hard wear resisting material.

The shiftable blades I2 are the initial or preliminary cutting elements acting to cut the maior outer portion of the well bore until worn to a given extent. at which time they retract to expose the xed -blad II for operation. The Ashiitable blades I2 are preferably. though not necessarily. asociated with the ilxed blades II.

In the preferred construction the blades I2 are dat plate-like parts having broadened lower portions and upwardly extending stems 2l of reduced width. The blades I2 are arranged to lie against the forward faces of the iixed blades II. The dat rear surfaces ofthe blades I2 are adapted to natly bear on the forward faces of the blades II'. The shiftable blades I2 are initially arranged to have their broad lower portions extend downwardly beyond the cutting edges I 5 of the fixed blades II. The lower portions of the blades I2 are bevelled away at their rear sides to provide lower cutting edges 22. The-cutting edges 22 may be straight and may slope downwardly and outwardly. The cutting edges 22 of the shiftable blades I2 may be of substantially the same length as the cutting edges II. The lower portions of the blades I2 have substantially vertical outer edges 28 which are preferably subilxed blades II. The active portions of the blades I2 are preferably hard faces or provided with inserts of hard wear resisting material to be long wearing. l

Means are provided for guiding the shiftable blades I2 for substantially vertical movement between the active positions where they extend downwardly beyond the fixed blades II and the retracted positions where the active parts of the fixed blades are exposed to act on the formation.

A vertically elongated slot 24 is provided in eachA xed blade II and an elongate guide 25 is arranged in each slot. The guides 25 are substantially T-shaped in horizontal cross section having I2 have been worn away.

longitudinal ribs or anges 26 extending along their outer edges. The shiftable blades I2 are provided with longitudinal slots 21 which receive the guides 25 with working clearance. The slots 21 are considerably longer than the guides 25 and extend downwardly beyond the guides when the blades I2 are in their normal or initial active positions.` The upper walls of the slots 2l may co-operate with the upper edges of the guides 25 when the blades I2 are in their active positions. The longitudinal ribs or flanges 26 of the guides 25 engage against the forward faces of the blades I2 to retain the blades in engagement with the forward faces of the iixed blades II. In assembling the tool the blades I2 are arranged against the forward faces of the blades II and the guides 25 are inserted into the registering grooves 2l and 2l. 'Ihe guides 25 are then iixed in place by welding the inner edge parts of the guides to the blades II at 28.

The means I3 operate to hold the blades I2 in the extended operative positions until the cutting parts of the blades I2 are worn away whereupon the means I3 releases to allow the blades I2 to retract or shift upwardly and thus condition the blades II for operation. In the embodiment of the invention illustrated in Figs. 1 to 4, inclusive, the means I3 comprise welding or welds 29 connecting or joining the blades I2 with the fixed blades II. The welds or welding 25 are positioned to be worn away through contact with the earth formation at the bottom of the well bore when the active parts of the blades The welds 29 are at the lower edges or cutting edges I! of the xed blades II and serve to Join the rear face portions ot the blades I2 to the lower edge portions of the blades II. '111e welds 25 may be continuous welds extending along the edges I9, as illustrated, ormay be interrupted welds, as desired. The welds 29 are of suillcient strength to dependably resist and transmit the drilling feed pressures to which the blades II may be subjected and t0 dependably resist the jars and shocks to which the tool issubiected when in operation.

Figs. 5 and 6 of the drawing illustrate'alternative or modified means for releasably holding the blades I2 in their extended active positions which may be used in substitution for the means Y I2 just described. In the construction shown in Fig. 5 of the drawing the shiftable primary blade I2 has a shoulder 3l on its rear side which engages against the edge I l of the fixed blade I I. The shoulder Il may be presented by a continuous elongate ridge on the blade I2 or may constitute the upper surfaces of spaced lugs on the blade. When the lower portion of the blade I2 wears away to the edge I! the shoulder 2l is worn away and the blade I2 is free to shift upwardly. In the construction shown in Fig. 6

stanuauy nush with the outer edges Il of the 0f the drawing one or more pins Il are provided on the blade` I2 and cooperate with the 'fixed blade Il releasably hold .the blade 12in its extended operative position. 'nie pins 3| may be set in sockets 32 inthe blade I2 and project from the rear face of the blade to engage upwardly against the edge I9 of theblade Il. The pins 3l are positioned to be worn away or at least weakened to a substantial extent when the active lower part of the blade I2 is worn down. When only partially worn. the pin or pins 3| may shear or break under the feed pressure applied to the bit or the drillers may impose additional pressure on the bit to break the pins 3| if this is deemed which lie in substantially vertical radial planesA spaced midway between the adjacent blades II. 'I'he rear sides of .the inner blades 33 may be bevelled away to provide the blades with suitable cutting edges 3l. The active parts of the blades 33 may be hard faced or provided with hard wear resisting material. The inner blades 33 are preferably shorter than the blades II and I2, that is, their cutting edges 3| preferably lie -in a plane spaced above the active edges of the outer blades II and I2. 'I'he blades 33 may be of substantial radial extent so that their outer portions overlap the outer blades II and I2 in their action on the earth formation. 'lhe invention contemplates the provision of shiftable initial cutting blades,similar to the blades I2, for the inner blades 33 to cut away the inner portion of the well bore during the nrst stages` of the drilling operation and to retract or shift upwardly when worn dull. However, in most instances the inner blades 33 are subjected to less wear than the outer blades II and itis unnecessary to provide the inner blades with shiftable preliminary blades. It is to be understood that while I have shown the invention embodied in a bit having two sets of cutting -parts II and 33, the invention is not limited to this application and may be embodied in well drilling tools having one, two or more sets of cutting parts.

Means is provided for flushing the cutting parts of the bit and for producing a suitable z turbulence at the bottom of the well bore. Spaced ports 36 may be provided in the lower part of the body In to communicate with the fluid opening I5. There may be three ports 36 arranged to discharge downwardly and outwardly from the lower end part of the body. As illustrated there is a port 36 discharging from the body I0 adjacent and in front of each pair of cutter blades II and I2. The fluid from the ports 36 effectively iiushes the adjacent blades I I and I2. Downwardly directed ports 31 may be formed in the lower part of the body I0 to join the fluid opening I5. The ports 31 are located to discharge downwardly immediately in front of the inner blades 33. 'I'he fluid from the-ports 31 washes the blades 33 and llnpinges against the bottom of the well bore to assist in the drilling action and to provide turbulence.

It is believed that the operation of the bit of the present invention will be readily understood beyond the fixed blades-Il the projecting cutting blades I2 act on the formation at the bottom of the well to drill or form the maior outer portion ofthe bore-and to cut the bore to gauge. The inner blades 33 cut away or breakdown the formation that may remain within the cut of the outer blades I2; The drilling operation may continue until .the active lower portions ofy the blades I2 are worn away to the welds 23. 'Ihe blades I2 remain effective in drilling away the earth formation imtii they are worn to the extent that the welds 29 engage the bottom of the well bore. The welds 29 quickly wear away through engagement with the earth formation. When a weld 29 wears away, the adjacent shiftable blade I2 retracts or shifts upwardly exposing the active lower portion of the adjacent blade II so that the blade II goes into operation. Up to this point the blades Il have received practically no wear and their new or unwom cutting edges I9 come into cutting engagement with-the earth formation. The rotary motion of the bit in the well bore causes the mud and cuttings to hold the shiftable blades I2 upwardly away from the bottom of the well bore and -the blades Il are free to act effectively. The drilling continues until the blades II are dulled or worn to a substantial extent.

'The bit embodying the sets of preliminary cutting blades I2 and secondary cutting blades II is long-lived, operating substantially twice as long as an ordinary well bit. The blades I2 autolmatically retract when wornv away and the blades II are automatically brought into operation at this time without the necessity of suspending the rotary drilling operation or of withdrawing the bit from the well. Following the operation of the bit and its withdrawal from the well the blades I2 may be removed and the blades II may bebuilt up or reconditioned. New blades I2 or reconditioned blades I2 may be assembled on the reconditioned bit. The bit is easy to repair or recondition.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appearto those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A well drilling tool comprising a body, a projecting cutting part on the body, a shiftable cutting part, and means for holding the shiftable cutting part in a position where itA extends beyond the first named cutting part and releasable to allow retraction of the shiftable cutting part from the cutting position when the shiftable cutting part is worn to given extent.

2. A well bit comprising a body, a part rigid with the body and projecting therefrom, said part having a cutting edge, a cutting member retraction of the member when the member is Y worn away to said edge.

3. A well bit comprising a body, a cutting part rigid with and projecting from the body, a cutv ting member shiftable on said part, and means -securing the member to said part to have an beyond the rigid blade to act on the bottom of the well and to prevent said edge from engaging the well bottom, and means for holding the shiftable blade in the position where it projects beyond the rigid blade and releasable through engagement with the well bottom when the shiftable blade has worn a given amount to allow upward retraction of the shiftable blade so that said edge is exposed to act on the well bottom.

' .5. A well drilling bit comprising a bit body, a blade rigid with the body and projecting downwardly therefrom to present a lower cutting edge, a shiftable blade adapted to project downwardly beyond the rigid blade to act on the bottom of the well and to prevent said edge from engaging the well bottom, and welding securing the shiftable blade to the rigid blade to project downwardly beyond the rigid blade, the welding being positioned to be worn away and released when the shiftable blade has worn to given point.

6. A well drilling bit comprising a bit body,

-a blade rigid with the body and projecting downwardly therefrom -to present a lower cutting edge, a preliminary cutting blade shiftable vertically on the rigid blade, and means for holding the preliminary blade against upward movement in a position where it projects downwardly beyond said edge to have preliminary cutting engagement with the bottom oi the well, said means including a part on the shiftable blade engaging upwardly against the rigid blade adapted to be worn away through engagement with the bottom of the well when the preliminary blade is worn to a given point.

7. A well drilling bit comprising a bit body, a blade rigid with the body and projecting downwardly therefrom to present a lower cutting edge, a preliminary cutting blade shiftable vertically on the rigid blade, and means for holding the preliminary blade against upward movement in a position where it projects downwardly beyond said edge to have preliminary cutting engagement with the bottom of the well, said means including a part on the shiftable blade engaging upwardly against said cutting edge and adapted to be drilled away by contact with the bottom of the well when the preliminary blade is worn away to said cutting edge.

8. In a well bit having a bit body, the combination of a projecting cutting blade rigid with the body, the cutting blade presenting a cutting edge, a shiftable cutting blade, means supporting the shiftable blade on the iirst named blade for movement between an active position where it projects beyond said edge to act on the earth formation and a retracted position where it exposes said edge for action on the earth formation, and an abutment on one of the blades cooperating with 'the other blade to hold the shittable blade in said active position and formed to be drilled away through contact with the earth formation esmas when the shiftable blade is worn to a given extent to allow the shittable blade to move to the retracted position.

9. In a well bit having a bit body, the combination of a projecting cutting blade rigid Iwith the boch, the cutting blade presenting a cutting edge, arshiftable cutting blade, means supporting the shitableblade on the iirst named blade for movement between an active position where it projects beyond said edge to act on the earth formation and a retracted position where it exposes said edge for action on the earth formation, and welding joining the two blades at said edge to hold the shiitable blade in the active position and adapted to be worn away through contact with the earth formation when the shiftable blade is worn to a given extent to free th'e shiftable blade for movement to the retracted position.

10. In a well bit having a bit body, the combination of a projecting cutting blade rigid with the body, the cutting blade presenting a cutting j edge, a shiftable cutting blade, means supporting the shiftable blade on the rst named blade fo: movement between an active position where it projects beyond said edge to act on the earth formation and a retracted position where it exposes said edge for action on the earth formation, and a pin on the shiftable blade cooperating with sai cutting edge to hold the shiftable blade in the active position and adapted to be worn away or broken to free the shiftable blade for movement to the retracted position when the shiftable blade is worn away to said edge.

11. A well drilling bit comprising a body for connection with a rotary well drilling string, a plurality of spaced cutting blades projecting downwardly from the body, a shirtable blade on each of the rst named blades, means for guiding the shiftable blades between active positions where they project downwardly beyond the first named blades and retracted positions wherethey expose the rst named blades for action, and means attaching the shitable blades -to their respective 11i-st named blades to hold the shiftable blades in their active positions and formed to be worn away through engagement with the earth formation to free the shiftable blade for movement to the retracted pomtions when the shiftable blades are worn to given extent.

12. A well drililng bit comprising a body for connection with a rotary well drilling string, a plurality of spaced cutting blades 'projecting downwardly from the body, a shiftable b lade on each of the-rst named blades, the shiftable blades having longitudinal slots, guides on the rst named blades extending into the slots and guiding the shiftable blades between active positions where they project beyond the rst named blades and -retracted positions where they expose the rst named blades for action, and welds ksecuring the shiftable blades to their respective rst named blades with the shiftable blades in their active positions and adaptedto be worn away to free the shiftable blades for movement to the retracted positions when the shiftable blades have been worn away to the lower edges f* named blades, and'welds securing the shiftable blades to their respective first named blades with the shiftable blades in their active positions and adapted to be worn away to free the shftable blades for movement to rthe retracted positions when the shiftable blades have been worn away to the lower edges of the i'lrst named blades.

MAX A. NEWTON. 

